Waveform Generator Teardown Is Nearly Empty

April 15, 2024 by 26 Comments

We always enjoy [Kerry Wong]’s insightful teardowns, and recently, he opened up a UTG1042X arbitrary waveform generator. Getting inside was a bit of a challenge since there were no visible screws. Turns out, they were under some stickers. We always dislike that because it is very difficult to get the unit to go back together.

Once open, the case reveals it is almost completely empty. The back panel has a power supply, and the front panel has all the working circuitry. The box seems to be for holding the foot and preventing the device from getting lost on your bench.

The power supply is unremarkable. There are a few odd output voltages. The main board is a bit more interesting, especially after removing the heat sink. There are two channels, but the board isn’t laid out, with a lot of segregation between the two channels. That makes sense with the output sections clustered together and the digital section with the CPU, FPGA, and the DAC in close proximity.

The other side of the board connects to a very simple display board. It would be interesting to compare this to a circa-1980s AWG, which would have been far more complicated.

Making a waveform generator with a microprocessor and a DAC isn’t hard. The hard part is the output stages and maximizing the operating speed.

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Do You Trust Your Cheap Fuses?

April 11, 2024 by 33 Comments

When a fuse is fitted in a power rail, it gives the peace of mind that the circuit is protected. But in the case of some cheap unbranded fuses of the type that come in kits from the usual online suppliers that trust can be illusory, as they fail to meet the required specification.

[Andreas Spiess] has used just these fuses for protection for years as no doubt have many of you, so it was something of a shock for him to discover that sometimes they don’t make the grade. He’s taken a look at the issue for himself, and come up with an accessible way to test your fuses if you have any of those cheap ones.

It’s an interesting journey into the way fuses work, as we’re reminded that the value written on the fuse isn’t the current at which it blows but the maximum it’s intended to take. The specification for fuses should have a graph showing how quickly one should blow at what currents above that level, and the worry was that this time would be simply too long for the cheap ones.

In the video below the break, he looks at the various set-ups required to test a fuse, and instead of a bank of large power supplies, he came up with a circuit involving an 18650 cell and three one ohm resistors in parallel. The resulting 1/3 ohm resistor should pass in the region of 10 A when connected across the 18650, so with a 5 A fuse in that circuit and a storage ‘scope he’s able to quickly test a few candidates. He found that the cheap fuses he had were slower to blow than a Bosch part but weren’t as worrisome as he’d at first thought. If you have any of these parts, maybe you should take a look at them too?

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Exploring The Bendix G-15’s Typewriter

April 10, 2024 by 3 Comments

The Bendix Corporation’s Bendix G-15 was introduced in 1956 as an affordable system for industrial and scientific markets. As with any computer system, a range of peripheral devices for input and output were available, which includes an electric typewriter. Produced by IBM, this typewriter was heavily modified by Bendix, with the version that [Usagi Electric] got their mittens on being equipped with a gigantic 28″ platen. With just power applied to the machine it will even still work as a regular electric typewriter, but it can do much more.

The bits that make an IBM electric typewriter into a Bendix G-15 accessory. (Credit: Usagi Electric)
The bits that make an IBM electric typewriter into a Bendix G-15 accessory. (Credit: Usagi Electric)

Most typewriters for the G-15 have a much smaller platen, as can be seen in the brochures for the system. The typewriter is connected together with other peripherals like plotters, card punches and tabulators via a coupler which uses a 5-bit interface. For the encoding on this interface no standard encoding is used, but rather 4 bits are used as data followed by 1 bit to indicate a command. In addition a number of other signal lines are used with the Bendix G-15, which allows control over the punch card reader and run status on the computer from the comfort of the typewriter’s desk.

In addition to the added electronics that communicate with the Bendix G-15, there are also solenoids and sensors which interface with the typewriter’s keyboard. This is what allows for command keys on the typewriter to be recorded separately along with the regular number and letter keys, in addition to the Bendix G-15 using the typewriter to automatically type on the paper. After a good cleaning session the typewriter’s basic functionality is restored, with the hope that once the Bendix G-15 over at the Usagi Farm can power up its DC circuit both will happily chat with each other. Color us excited.

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Hackaday Links: March 31, 2024

March 31, 2024 by 5 Comments

Battlelines are being drawn in Canada over the lowly Flipper Zero, a device seen by some as an existential threat to motor vehicle owners across the Great White North. The story started a month or so ago, when someone in the government floated the idea of banning devices that could be “used to steal vehicles by copying the wireless signals for remote keyless entry.” The Flipper Zero was singled out as an example of such a nefarious device, even though relatively few vehicles on the road today can be boosted using the simple replay attack that a Flipper is capable of, and the ones that are vulnerable to this attack aren’t all that desirable — apologies to the 1993 Camry, of course. With that threat hanging in the air, the folks over at Flipper Devices started a Change.org petition to educate people about the misperceptions surrounding the Flipper Zero’s capabilities, and to urge the Canadian government to reconsider their position on devices intended to explore the RF spectrum. That last bit is important, since transmit-capable SDR devices like the HackRF could fall afoul of a broad interpretation of the proposed ban; heck, even a receive-only SDR dongle might be construed as a restricted device. We’re generally not much for petitions, but this case might represent an exception. “First they came for the Flipper Zero, but I did nothing because I don’t have a Flipper Zero…”

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Luggable Cyberdeck Can Still Be A Luggable PC

March 4, 2024 by 3 Comments

In the 80s and early 90s, there existed a class of personal computers that are no longer around today — the luggable. Planted firmly between a desktop and a laptop, these machines were lovingly called so because they were portable, but just barely. Think Kaypro, Osborne, or the Compaq Portable.

First things first — this lovely 1990-era industrial luggable has not been gutted according to [D1g1t4l_G33k]. The chassis, CRT, power supply, and ISA backplane are original and still intact, and they still have all the parts to restore it to its original DOS 3.1 form.

What [D1g1t4l_G33k] did do is replace the 386x-based ISA SBC with a 2005 AMD LX-600 Geode at 366 MHz. Gone are the ISA data acquisition cards and 80 MB SCSI hard drive, replaced with a 32 GB compact flash drive. The floppy drive is functional, too. Now it sits on a cart next to the workbench running AntiX Core 19.5, functioning happily as an AVR development workstation.

Having an old luggable to mess with in the first place isn’t a requirement. We’ve seen a modern take on the luggable, and here’s one with three monitors.

New Modelling Shows That Flat Protoplanets Might Be A Thing

February 20, 2024 by 23 Comments
Surface density of the benchmark run disc (in g cm−2). The disc becomes gravitationally unstable and fragments. Four of the fragments or protoplanets are followed until they reach density 10−3 g cm−3. (Credit: Fenton et al., 2024)
Surface density of the benchmark run disc (in g cm−2). The disc becomes gravitationally unstable and fragments. Four of the fragments or protoplanets are followed until they reach density 10−3 g cm−3. (Credit: Fenton et al., 2024)

While the very idea of a flat planet millions of years after its formation is patently ridiculous, recent modelling shows that during the protostar phase – where material from a nebula is drawn around a hydrostatic core into an accretion disc – it is likely that many of of the protoplanets which form inside a fragmentary protostar accretion disc take on a strongly oblate spheroid shape, rather than a spherical one. This according to [Adam Fenton] and [Dimitris Stamatellos], who ran half a million CPU hours worth of simulation time at the UK’s DiRAC HPC facility, per the University of Central Lancashire (UCLan) press release.

The research was published in the February 2024 issue of Astronomy & Astrophysics, titled The 3D structure of disc-instability protoplanets.

Where this research is essential is not just in our understanding of how our own solar system came to be – including our own oblate spheroid Earth – but also in interpreting what we observe via the Hubble Space Telescope, James Webb Space Telescope and others as we examine areas of the observable Universe such as the Orion Nebula, which is one of the regions with the most actively forming stars. By comparing these simulations with observations, we may find that the simulation matches perfectly, matches partially, or perhaps not at all, which provides data to refine the simulation, but also helps to reconsider how observations were previously interpreted.